Bake object with many parts
I suggest you to "explode" the geometry and then bake,
explode means; you take everything apart so there is a margin between they, you have to do this for every pass except the ambient occlusion pass

-separate the pieces when there is a weird angle(not sure of this last pàrt)

Supplementary:
this video shows the process done in maya and substance painter, but its the same for blender
https://www.youtube.com/watch?v=3fY3LEnoRxU&amp;t=7s